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Some Question New Water Release Regime Intended To Return Salmon, Steelhead To Upper Deschutes
Posted on Friday, August 12, 2011 (PST)

Fishermen accustomed to targeting steelhead in the lower Deschutes River are again steamed about water releases 100 miles upstream which they say are warming the water and making it less inviting, and less hospitable, for fish.

 

“The water down there isn’t any warmer than it usually is,” Portland General Electric senior biologist Don Ratliff says of the water flowing from central Oregon’s Deschutes River into the Columbia River.

 

Anglers disagree.

 

“We’re definitely having temperature issues,” said fishing outfitter Grant Putnam, one of those who feels that changed water releases in 2010 and again this year from Pelton Round Butte complex of dams, which is co-owned by PGE and the Warm Springs Tribes, are warming the river in early summer.

 

The mouth of the Deschutes has long been known as a place where fish headed up the Columbia can rest and escape what is normally a warmer Columbia River.

 

Those fish either move on toward their natal streams after the Columbia cools, or in some cases stray up the Deschutes to spawn along with wild and hatchery produced local fish. In the interim they are the targets of sport fishers.

 

As part of the federal licensing agreement for the dams, a 273-foot-tall juvenile fish collection/water mixing tower was installed and began operating in 2010. One of its primary functions is to allow Round Butte operators to mix warmer water from near the surface of Lake Billy Chinook with colder water from the bottom of the reservoir. Round Butte is the farthest upstream of the three dams in the complex and holds back water from the upriver Deschutes and the Crooked and Metolius rivers.

 

Water quality permits issued by the tribes and Oregon’s Department of Environmental Quality as part of the relicensing process prescribe a mixing of the water sent through the dams’ turbines that, for the most part, is warmer in early summer and cooler in late summer.

 

In the more than 40 years since the dams were built all of the output had come from the lowest part of the reservoir where the coldest water rests. Late in the summer, heat buildup in the stored water was reflected in released water that was warmer than it would have been if the Deschutes sources were allowed to mix naturally, Ratliff said.

 

The mixing tower is intended to mimic Deschutes water temperatures that existed before the dams, when the cool waters of the Metolius and the warmer upper Deschutes and Crooked mixed naturally just above where Round Butte Dam now stands.

 

Those involved in the planning envisioned creating an environment that more closely mirrors conditions in which steelhead and chinook and sockeye salmon populations evolved.

 

Ratliff and the Warm Springs Water and Soil Department Manager Deepak Sehgal said that the early summer water releases, just two or three degrees warmer than before the mixing tower began operating, only alter river temperature for the first several miles downstream. After that, the sun, movement and warm air in central Oregon’s high desert, canyon country serve to bring the water temperature back to “normal” by the time it reaches the river mouth.

 

The operational changes “haven’t had any kind of significant effects” on water temperature 100 miles downstream at the mouth, Sehgal said.

 

And the cooler water in river reaches just below the dam should have positive effects. The warmer early summer flows allows aquatic life, including fish, to blossom and grow on a more normal schedule. The late summer cooling helps bring river pH and dissolved oxygen to healthier levels and helps bring down water temperatures.

 

Fishing guide Brad Staples insists that the new system is out of whack. Northwest rivers normally flow cold early on as the snowpack melts down, and gradually warm as the summer season progresses, not the other way around.

 

“That’s what I don’t understand,” Staples said of the warmer (than prior to tower operations), then colder releases.

 

Staples said he and other fishers are working to get a meeting with state and tribal officials to discuss what can be done about the situation.

 

The 401 water quality permits call for the maintenance of outflows within one degree of the “natural thermal potential.” That potential is a complicated calculation that assesses the volume and temperature of the waters of the Crooked, Deschutes and Metolius rivers feeding into the lake, and then factoring in distance, depth, surface area and ambient air temperatures to calculate what the temperature of the water below the dams would have been without the reservoirs and dams in place.

 

Putnum, who takes measurements early morning, noon and late afternoon each day he is fishing, said temperatures at the mouth have been “2-3 degrees warmer on average from they should be” in early summer. And those flows are also about that much warmer than the Columbia, which is atypical. High flows coming down from record snowpacks in the upper Columbia and Snake have persisted. They along with cooler than normal air temperatures across the Columbia basin have served to keep Columbia River water cooler than normal this year.

 

Staples and Putnam say that conditions have indeed changed since the tower began operating 100 miles upstream.

 

Those changes, in turn, “have affected our catch rates,” Putnam said. “The steelhead have not been biting as well as we would like.”

 

The Oregon Department of Fish and Wildlife’s regional fishery manager, Rod French, likes the fish recovery goals lined out in the licensing agreement, which include measures to reintroduce steelhead and salmon above the dams and provide passage at the dams, as well as implement habitat improvements downstream. But he doesn’t leave the tower blameless.

 

“It’s definitely had an effect” on water temperatures downstream, French said. “It’s warmer in the summer than it has been historically (since the dams were built).”

 

The steelhead fishing season in the Deschutes started slow, probably because a high, cool Columbia seemed to delay the upstream migration.

 

“Fishing was not as good in July” as it is normally and water condition would well be a factor, he said. There has been no evidence of fish mortalities of other ill effects from the warmer water, French said.

 

“But the temperatures have cooled a bit and the fishing has gotten better,” he said.

 

The computer-programed water mixing at Round Butte has performed well this year, PGE’s Ratliff said.

 

In order to follow changing natural thermal potential projection, dam operators began mixing in more cold water July 1, going to a 15 percent cool/85 percent warm mixture, then shifted to 20-80 percent July 14 and 25-75 July 19.

 

“We were still chasing it,” Ratliff said of trying to keep pace with a changing thermal potential value. The mixture was changed to 30 percent cool/70 percent August 1. He said Thursday that another 5 percent cool would likely be added within a few days.

 

French said it is still too early to tell the level of steelhead straying into the Deschutes this year. And even when that level is estimated via a sampling of the run at the Sherars Falls trap, it won’t be known if the river temperatures influenced the fish. The Deschutes is known for attracting relatively high levels of strays, though the number varies greatly from year to year.

 

It is estimated that 15,700 strays, 9,500 Deschutes River steelhead produced at Round Butte Hatchery and 4,200 wild local fish migrated past Sherars Falls (river mile 40) during 2009-2010 and that 5,150 strays, 7,250 wild local steelhead and 4,897 Round Butte Hatchery fish were estimated in 2010-2011.

 

Since 1977-78 the estimated number of strays has ranged from less than 1,000 to more than 23,000. A certain number of the strays counted at Sherars Falls each year backtrack and resume their journey up the Columbia.

 

To see a fact sheet about Round Butte operations go to:

http://www.deschutespassage.com/news/?p=80

 

 

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